A camshaft adjustment system is used for adjusting the phase position between a camshaft and a crankshaft in an internal combustion engine. For this purpose, a rotor is typically mounted in a stator so that it can move with a rotating motion. The stator of the camshaft adjustment system is locked in rotation with the crankshaft. The rotor is locked in rotation with the camshaft. The phase position between the crankshaft and the camshaft is adjusted by means of a relative rotation of the rotor relative to the stator. For common camshaft adjustment systems of today, the rotor is rotated hydraulically relative to the stator.
A central screw that presses the rotor arranged inside the stator against an end face of the camshaft is one technical possibility for connecting the camshaft adjustment system to the crankshaft. Here, the central screw engages in an internal thread of the camshaft.
Such a camshaft adjustment system, wherein the connection to the camshaft is provided by means of a central screw, is proposed, for example, in DE 10 2006 036 034 A1. The ends of the camshaft and the drive element of the camshaft adjustment system have uneven microscopic or macroscopic features, so that a positive-fit connection is established in addition to a non-positive connection for transferring the driving moment.
For increasing the adhesive friction between the components that are connected with a non-positive fit, friction or clamping disks are also used whose material or their surface is selected according to the friction or contact partners. A clamping disk can reduce the normal force required for the coupling and thus the load on the clamped components.
Known friction or clamping disks are constructed, for example, as thin steel foils with a friction increasing and/or wear-resistant hard coating. Hard coatings are known, for example, from DE 10 2008 013 966 A1 or DE 19 850 048 A1.
The most cost-effective procedure is to install a clamping disk after the camshaft adjusting unit has already been assembled. The clamping disk is mounted on the camshaft side on the rotor located in the stator. The camshaft adjusting unit with the mounted clamping disk is then connected to the camshaft by means of a central screw.
For transferring the load moment and guaranteeing the axial position of the camshaft adjusting unit relative to the camshaft flange, exactly one clamping disk must be provided to which the geometry of the components is tuned. By means of this geometry, after successful installation, the desired normal force on the clamping disk is produced, so that a non-positive or friction-fit connection of the camshaft adjusting unit to the camshaft is guaranteed. Such a clamping disk has, for example, a thickness between 0.1 and 1.0 mm. Therefore, the installation can easily be performed incorrectly by inserting no or multiple clamping disks. This has the undesirable result that the camshaft adjustment system is not functional.
Furthermore, in the transport of the preassembled camshaft adjusting unit on the motor and in the installation on the camshaft, the inserted clamping disk must remain as fixed as possible. On the other hand, the clamping disk is a wear part, so that the simplest possible disassembly must also be given.